Photolithographic fabrication of semiconductor components, such as integrated circuits and dynamic RAM (DRAM) chips, is customary in the semiconductor industry. In photolithographic fabrication, light may be used to cure or harden a photomask that is used to form a pattern of conductive, semiconductive, and insulative components in the semiconductor layer. The resulting pattern of conductive, semiconductive, and insulative components on the semiconductor layer form extremely small microelectronic devices, such as transistors, diodes, and the like. The microelectronic devices are generally combined to form various semiconductor components.
The density of the microelectronic devices on the semiconductor layer may be increased by decreasing the size or geometry of the various conductive, semiconductive, and insulative components formed on the semiconductor layer. This decrease in size allows a larger number of such microelectronic devices to be formed on the semiconductor layer. As a result, the computing power and speed of the semiconductor component may be greatly improved.
The lower limit on the size, often referred to as the linewidth, of a microelectronic device is generally limited by the wavelength of light used in the photolithographic process. The shorter the wavelength of light used in the photolithographic process, the smaller the size or linewidth of the microelectronic device that may be formed on the semiconductor layer. Semiconductor component fabrication may be further improved by increasing the intensity of the light used in the photolithographic process, which reduces the time the photomask material needs to be radiated with light. Accordingly, the greater the intensity of light used in the photolithographic process, the shorter the time the photomask material is radiated with light. As a result, the semiconductor components may be produced faster and less expensively.
Extreme ultra-violet (EUV) light has a very short wavelength and is preferable for photolithographic fabrication of semiconductor components. Conventional methods of generating EUV light typically include impinging an energy source into a hard target to produce, or radiate, EUV light. The energy source may be a high energy laser, electron beam, an electrical arc, or the like. The hard target is generally a ceramic, thin-film, or solid target comprising such materials as tungsten, tin, copper, gold, solid xenon, or the like. Optics, such as mirrors and lenses, are used to reflect and focus the EUV light on the semiconductor layer.
Conventional energy beam systems and processes suffer from numerous disadvantages. One disadvantage of conventional methods of producing EUV light is that debris from the energy source/target interaction is produced during the production of the EUV light. The production of debris increases with the intensity of the energy source and results in the target being degraded and eventually destroyed. The debris may coat and contaminate the optics and other components of the energy beam system, thereby reducing the efficiency and performance of the system. The reduced performance requires a greater frequency of system maintenance and system downtime.